1. Field of the Invention
The present invention relates generally to wireless communications. More particularly, it relates to securing communications with wireless devices over a short distance.
2. Background of the Invention
The Institute of Electrical and Electronics Engineers (IEEE) has promulgated standards designated 802.11 and 802.15 for short-distance wireless networks. These standards describe protocols and procedures that allow wireless devices in a Personal Operating Space (WLAN, PICONET, PAN) or IEEE Personal Area Network to communicate.
Generally speaking, a short-distance wireless device designed to operate as part of a PICONET, WLAN or PAN has a transmission radius of at least 10 meters. This is based on, for example, a short-distance wireless device having a 2.4 GHz, 1 milli-watt transmitter operating at about 1 Mb/s. Multiple short-distance wireless devices having peer-to-peer communications capabilities can operate in overlapping PICONETs or PANs to form part of a larger communications network (termed a Scatter Net).
The general trend in short-distance wireless communications has been to increase the operating range of conventional PICONETs and PANs. For example, more recent PICONET and PAN standards call for a 30-meter operating range. This increase in range is disadvantageous for short-distance wireless applications where security is important. For example, by increasing the transmission range of short-distance wireless devices in a PICONET or PAN, it becomes more difficult to limit the number of wireless devices that receive network messages, and as a result, it becomes more likely that network message will be received and either erroneously acted upon by an unintended recipient or perhaps even hacked by an unauthorized recipient. Encrypting network messages can overcome the issues associated with increased operating ranges, but using encryption makes it difficult for wireless devices to seamlessly enter and exit a conventional PICONET or PAN.
What is needed are new, more secure systems and methods for short-distance wireless communications that overcome the limitations of a conventional PICONET or PAN. Specifically what is needed is a method of exchanging session keys between a user entering the PICONET and a trusted body supervising the physical location.